The present invention relates to a novel technique for forming indene from allylbenzene.
U.S. Pat. No. 3,452,032 describes a process for producing cinnamaldehyde wherein allylbenzene and oxygen are contacted with certain metal oxide complexes known to function as oxidation and ammoxidation catalysts. In accordance with the present invention, it has now been discovered that indene can be produced in this reaction in significant amounts if the oxide complex catalyst contains tungsten in significant amounts.
Accordingly, the present invention provides a novel process for producing indene from allylbenzene wherein allylbenzene and oxygen are contacted with an oxide or an oxide complex catalyst containing at least 30 atom % tungsten, the percent being based on the metal atoms in the complex excluding oxygen.
More specifically, the present invention provides a process for producing indene from allylbenzene where allylbenzene and oxygen are contacted with a phosphorous and molybdenum-free oxide or oxide complex catalyst of the following formula: EQU A.sub.a B.sub.b C.sub.c WO.sub.x
wherein
A is at least one element selected from the group consisting of periods IA, IIA of the Periodic Table and Tl,
B is at least one element selected from the group consisting of Cu, Co, Fe, Mn, Cr and Ce, and
C is at least one element selected from the group consisting of Bi, Sb, U, V and Sn, and further
wherein
a equals 0 to 10,
b equals 0 to 10,
c equals 0 to 10, and
x is a number sufficient to satisfy the valence requirements of the other elements present.